XOR Gateway
Hello,
I have a project which have the XOR gateway en when I run it its gives me this error:
This is what I coded in my XOR gateway:
if(studentId !="null"); the process must continue or if(studentId =="null"); the process must alert the user to input the studentId. but when I run this error occurs.
Exception in thread "Thread-4" org.jbpm.workflow.instance.WorkflowRuntimeException: [validatingStudentId.bpmn:1 - Gateway:5] -- Exception when trying to evaluate constraint Accept in split Gateway
at org.jbpm.workflow.instance.impl.NodeInstanceImpl.trigger(NodeInstanceImpl.java:130)
at org.jbpm.workflow.instance.impl.NodeInstanceImpl.triggerNodeInstance(NodeInstanceImpl.java:205)
at org.jbpm.workflow.instance.impl.NodeInstanceImpl.triggerCompleted(NodeInstanceImpl.java:164)
at org.jbpm.workflow.instance.impl.ExtendedNodeInstanceImpl.triggerCompleted(ExtendedNodeInstanceImpl.java:47)
at org.jbpm.workflow.instance.node.StateBasedNodeInstance.triggerCompleted(StateBasedNodeInstance.java:162)
at org.jbpm.workflow.instance.node.StateBasedNodeInstance.triggerCompleted(StateBasedNodeInstance.java:143)
at org.jbpm.workflow.instance.node.WorkItemNodeInstance.triggerCompleted(WorkItemNodeInstance.java:239)
at org.jbpm.workflow.instance.node.HumanTaskNodeInstance.triggerCompleted(HumanTaskNodeInstance.java:90)
at org.jbpm.workflow.instance.node.WorkItemNodeInstance.workItemCompleted(WorkItemNodeInstance.java:301)
at org.jbpm.workflow.instance.node.WorkItemNodeInstance.signalEvent(WorkItemNodeInstance.java:277)
at org.jbpm.workflow.instance.impl.WorkflowProcessInstanceImpl.signalEvent(WorkflowProcessInstanceImpl.java:326)
at org.drools.process.instance.impl.DefaultWorkItemManager.completeWorkItem(DefaultWorkItemManager.java:116)
at org.jbpm.process.workitem.wsht.GenericHTWorkItemHandler$TaskCompletedHandler.handleCompletedTask(GenericHTWorkItemHandler.java:221)
at org.jbpm.process.workitem.wsht.GenericHTWorkItemHandler$TaskCompletedHandler$1.run(GenericHTWorkItemHandler.java:187)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.RuntimeException: Exception when trying to evaluate constraint Accept in split Gateway
at org.jbpm.workflow.instance.node.SplitInstance.internalTrigger(SplitInstance.java:79)
at org.jbpm.workflow.instance.impl.NodeInstanceImpl.trigger(NodeInstanceImpl.java:124)
... 14 more
Caused by: java.lang.RuntimeException: unable to execute ReturnValueEvaluator
at org.jbpm.process.instance.impl.ReturnValueConstraintEvaluator.evaluate(ReturnValueConstraintEvaluator.java:130)
at org.jbpm.workflow.instance.node.SplitInstance.internalTrigger(SplitInstance.java:72)
... 15 more
Caused by: java.lang.RuntimeException: Constraints must return boolean values: if(studentId !=" null"); returns null
at org.jbpm.process.instance.impl.MVELReturnValueEvaluator.evaluate(MVELReturnValueEvaluator.java:119)
at org.jbpm.process.instance.impl.ReturnValueConstraintEvaluator.evaluate(ReturnValueConstraintEvaluator.java:128)
... 16 more
